[unreadable] Marijuana is one of the most widely abused drugs during adolescence and may be a gateway to other illicit drug use, yet there is no consensus about the best approach to the treatment of adolescents with marijuana use disorders. Contingency management (CM) procedures have been shown to be efficacious with many difficult to treat substance dependent populations. The immediate and tangible positive reinforcement provided by CM may be particularly appealing to adolescents. The proposed study will assess the feasibility of implementation of CM procedures in a community treatment program and provide preliminary data concerning the efficacy of contingency management for adolescents with marijuana abuse and dependence. Using the "abstinence bowl" incentive procedure (described in methods) will reduce the cost of implementation. Since this particular procedure has not been explored in the adolescent population, modifications (such as age appropriate prizes) will be made to fit this population. The specific aims of this R-21 exploratory application are: 1. To implement a contingency management intervention in an adolescent treatment program at a community-based substance abuse treatment program; 2. To assess the impact of a contingency management intervention on marijuana use as determined by UDS in adolescents with marijuana abuse or dependence; and 3. To assess the impact of a contingency management intervention on retention in treatment for adolescents with marijuana abuse or dependence. The primary outcome measures in this randomized study will be abstinence from marijuana and retention in treatment. Those randomized to the incentive group will be awarded chances to draw for prizes when urine drug screens are negative for drugs. The number of draws will increase with consecutive negative screens. The noncontingent group will receive a fixed number of draws per visit regardless of urine drug screen results. Both groups will be enrolled in outpatient substance abuse treatment and submit twice weekly urine drug samples for 12 weeks. The proposed CM intervention holds much promise for success. This program has demonstrated efficacy with drug dependent adults and the immediate and tangible rewards are likely to be particularly appealing to adolescents. If findings are positive, a larger efficacy study will be proposed. [unreadable] [unreadable]